RDMA/mlx5: Use get_zeroed_page() for clock_info

get_zeroed_page() returns a virtual address for the page which is better
than allocating a struct page and doing a permanent kmap on it.

Cc: stable@vger.kernel.org
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mlx5/main.c

@@ -2070,11 +2070,12 @@ static int mlx5_ib_mmap_clock_info_page(struct mlx5_ib_dev *dev,
 		return -EPERM;
 	vma->vm_flags &= ~VM_MAYWRITE;
 
-	if (!dev->mdev->clock_info_page)
+	if (!dev->mdev->clock_info)
 		return -EOPNOTSUPP;
 
 	return rdma_user_mmap_page(&context->ibucontext, vma,
-				   dev->mdev->clock_info_page, PAGE_SIZE);
+				   virt_to_page(dev->mdev->clock_info),
+				   PAGE_SIZE);
 }
 
 static int uar_mmap(struct mlx5_ib_dev *dev, enum mlx5_ib_mmap_cmd cmd,

drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c

@@ -535,23 +535,16 @@ void mlx5_init_clock(struct mlx5_core_dev *mdev)
 	do_div(ns, NSEC_PER_SEC / HZ);
 	clock->overflow_period = ns;
 
-	mdev->clock_info_page = alloc_page(GFP_KERNEL);
-	if (mdev->clock_info_page) {
-		mdev->clock_info = kmap(mdev->clock_info_page);
-		if (!mdev->clock_info) {
-			__free_page(mdev->clock_info_page);
-			mlx5_core_warn(mdev, "failed to map clock page\n");
-		} else {
-			mdev->clock_info->sign   = 0;
+	mdev->clock_info =
+		(struct mlx5_ib_clock_info *)get_zeroed_page(GFP_KERNEL);
+	if (mdev->clock_info) {
 		mdev->clock_info->nsec = clock->tc.nsec;
 		mdev->clock_info->cycles = clock->tc.cycle_last;
 		mdev->clock_info->mask = clock->cycles.mask;
 		mdev->clock_info->mult = clock->nominal_c_mult;
 		mdev->clock_info->shift = clock->cycles.shift;
 		mdev->clock_info->frac = clock->tc.frac;
-			mdev->clock_info->overflow_period =
-						clock->overflow_period;
-		}
+		mdev->clock_info->overflow_period = clock->overflow_period;
 	}
 
 	INIT_WORK(&clock->pps_info.out_work, mlx5_pps_out);
@@ -599,8 +592,7 @@ void mlx5_cleanup_clock(struct mlx5_core_dev *mdev)
 	cancel_delayed_work_sync(&clock->overflow_work);
 
 	if (mdev->clock_info) {
-		kunmap(mdev->clock_info_page);
-		__free_page(mdev->clock_info_page);
+		free_page((unsigned long)mdev->clock_info);
 		mdev->clock_info = NULL;
 	}
 

include/linux/mlx5/driver.h

@@ -681,7 +681,6 @@ struct mlx5_core_dev {
 #endif
 	struct mlx5_clock        clock;
 	struct mlx5_ib_clock_info  *clock_info;
-	struct page             *clock_info_page;
 	struct mlx5_fw_tracer   *tracer;
 };